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A B767 was dispatched with the high pressure bleed shut-off valve deferred as inoperative per the MEL. The wrong valve was locked closed due to a confusing diagram in the maintenance manual.
| Attributes | |
| ACN | 668795 |
| Time | |
| Date | 200508 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B767 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : takeoff roll ground : maintenance |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| ASRS Report | 668795 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : non compliance with mel non adherence : published procedure non adherence : far |
| Independent Detector | aircraft equipment other aircraft equipment : eicas bleed fail warning other flight crewa other flight crewb |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other Other |
| Factors | |
| Maintenance | contributing factor : work cards contributing factor : schedule pressure performance deficiency : logbook entry performance deficiency : repair performance deficiency : non compliance with legal requirements |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Aircraft Chart Or Publication Environmental Factor |
| Primary Problem | Maintenance Human Performance |
Narrative:
While performing MEL procedures; I mis-identified the pressure regulating valve for the high pressure shut-off valve; thus locking the improper valve in the closed position. The maintenance manual figures are somewhat confusing. The engine identifications are at the bottom of the page; while trying to locate a clearer picture of the valve; I inadvertently ended back on the clearest picture of all; which happened to be on the CF6-80A. The final decision was made from the valve's position to the precooler. Other contributing factors are the additional mels I installed for this aircraft; along with mels for this item complicated this task. Operations' decision to board the aircraft and it being departure time; added additional pressure to complete task and dispatch aircraft in a timely manner. Aircraft ground interrupted; returned to gate and incident was corrected.
Original NASA ASRS Text
Title: A B767 WAS DISPATCHED WITH THE HIGH PRESSURE BLEED SHUT-OFF VALVE DEFERRED AS INOP PER THE MEL. THE WRONG VALVE WAS LOCKED CLOSED DUE TO A CONFUSING DIAGRAM IN THE MAINT MANUAL.
Narrative: WHILE PERFORMING MEL PROCS; I MIS-IDENTIFIED THE PRESSURE REGULATING VALVE FOR THE HIGH PRESSURE SHUT-OFF VALVE; THUS LOCKING THE IMPROPER VALVE IN THE CLOSED POSITION. THE MAINT MANUAL FIGURES ARE SOMEWHAT CONFUSING. THE ENG IDENTIFICATIONS ARE AT THE BOTTOM OF THE PAGE; WHILE TRYING TO LOCATE A CLEARER PICTURE OF THE VALVE; I INADVERTENTLY ENDED BACK ON THE CLEAREST PICTURE OF ALL; WHICH HAPPENED TO BE ON THE CF6-80A. THE FINAL DECISION WAS MADE FROM THE VALVE'S POSITION TO THE PRECOOLER. OTHER CONTRIBUTING FACTORS ARE THE ADDITIONAL MELS I INSTALLED FOR THIS ACFT; ALONG WITH MELS FOR THIS ITEM COMPLICATED THIS TASK. OPS' DECISION TO BOARD THE ACFT AND IT BEING DEP TIME; ADDED ADDITIONAL PRESSURE TO COMPLETE TASK AND DISPATCH ACFT IN A TIMELY MANNER. ACFT GND INTERRUPTED; RETURNED TO GATE AND INCIDENT WAS CORRECTED.
Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.